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high Strain, wherein the Author too often delivers it; but in a discreet, sober and moderate Sense." And having given this Advertisemenë in the general, we proceed with our Account
of the remaining Part of the Work. Process. It was above observed, that there are 88
Processes upon Vegetables, the first of which is
already described at large. The Second shews Decoétions, the Manner of making Decotions; and is per
formed upon the Remains of the former. And as that manifested the Effect of 85 Degrees of a dry Heat upon a recent Plant ; so this thews what Effect a moist Heat, or Fire and Water in conjunction, will have upon the same Subject; when the Heat is gradually raised from 85 to 212 Degrees; that is, a Heat sufficient to make Water boil.
PROCESS 3. exhibits the Method of makRobs, ing Robs, Jellies, Extracts, &c. and is perExtracts, formed upon the Decoction of the second, by eva. &c.
porating the superfluous Water, and by reducing the Remainder to a thick or somewhat folid Consistence; whence we understand what Parts of Vegetables are soluble in boiling Water.
THE fourth shews the manner of burning or calcining Vegetables to white Ashes, by means , of an open Fire ; and is performed upon the
Remains of the second Process ; where it is remarkable that the external Figure of the Planc
remains perfect in the Alhes. 5. 6. The fifth and fixth are Repetitions of the
fourth, upon Subjects not robbed of their Salt by Decoction. These Processes Thew, (1.) That Water affifted with the utmost Force of Fire, diffolves not the Solids ; but only the Juices of Vegetables. (2.) That Fire employ'd by icself, has scarce a greater Eficacy upon Vege
tables, or rather extracts less from them, than boiling Water ; as leaving their Salt behind,'.. which is dissolved by Water. (3.) That boiling Water extracts even an inflammable Substance from Vegetables. (4.) That the Oil and Salt naturally mixt in Plants, are together soluble in boiling Water, so as to remain united ; tho'. they are still separable by an open Fire. (5.) That the Juices of Plants and Animals in a healthy State, are naturally a kind of saponaceous Mixture, that becomes morbid upon the Separation of their Oil or Salt. And (6) That the elementary Differences of Plants confift in their Juices; the more fixed and earthy Parts being alike in them all.
The seventh Process shews the manner of obtaining the essential or natural Salts of Plants;Vegetable by suffering their Juices, properly purified and Salts. defended, to stand for some Months in a cool
The eighth thews how the native Salt, or 8. Tartar, is obtained from vegetable Juices, after they have been fermented, or made into Wines; viz. by letting the purified Liquor stand in the Cask to shoot.
The ninth shews the way of preparing that 9::: called the Medicated Salt of Tachenius'; by torrifying a Plant, or burning it black, with a stired Heat ; then elixating the black Ashes, and evaporating the Liquor to a Salt. And Salts thus prepared, the Author highly recommends for their medicinal Virtues ; and largely describes the Method of using them.
The tentb Process is a Repetition of the 10. ninth, upon a dry'd Plant; the former being upon a green one.
... The eleventb shews the common way of
procuring the fixed Salts of Vegetables, by Calcination, Solution in Water, and Evaporation.
THE twelfth shews the Method of preparing the fixed, corrosive, alcaline Sorts of Ve. getables, and running those Salts per deliquium : being a farther Prosecution of the ninth, tenth,
and eleventh. 13.
The thirteenth shews the Method of making the common Caustick, or a highly corrosive. Salt, with Por-ash and Quick-lime,for chirurgical Uses. And thụs the Power of Chemistry upon fix'd alkaline Salts, the Author tells us, is carried as far as he was capable.
These Processes with regard to Salts make it appear, (1.) That fixed Salt is procurable by burning certain vegetable Subjects ; some whereof afford a greater, and some a less Proportion thereof. (2.) That it is obtained only by means of Fire. (3.): That this Salt is not the native Salt of the Plant. And (4.) That it is of different Species or Degrees of Strength ; according as the Fire has acted more or less thereon.
The fourteenth Process shews that fixed vegetable alkaline Salt yields a bitter, crystalline, hard, fixed, unalkaline and somewhat vitreous Salt, by being diffolved in Water. This, thoa common Observation, its Doctrine is of an extraordinary nature ; but not duly prosecuted by the Author. And thus concludes the che
mical History of Salts. The Hiftory We next proceed to Distilled Waters ; the of distilled Männer of obtaining which is delivered in four Waters. Processes.
PROCESS 15. therefore thews the common Method of distilling simple Waters, or
what Parts of recent Vegetables rise with the Heat of boiling Water, and what remain behind: Whence it appears, that the fapid and odorous Parts of Plants chiefly exhale by such Treatment. And here the Rule is to stop as soon as the Water comes over without any remarkable Scent and Taste of the Subject.
The fixteenth shews the Method of cohoba-, 16. ting simple Waters ; or returning them back upon a fresh Parcel of the fame Subject ; and distilling them off again, so as to make chem richer.
The seventeenth Thews the Manner of di- 19: stilling a Water from Plants, after they have been fermented with Water, and Yeaft, or Honey, &c. which Method, cho' it somewhat alters the Virtues of the Subject, has considerable Uses.
The eighteenth shews the Manner of distilling per Defcenfum , or downwards ; a Process of little Significance.
The nineteenth Process is perform'd upon - 10. the Remains of the fifteenth, fixteenth, sevenceenth and eighteench Processes ; to shew what was left behind in those Operacions ; after the same manner as the fifth, fixth, ninch, tenth, and eleyench Processes were performed. And · this concludes the Business of distilling Waters.
VEGETABLE Oils come next in order. The 28. twentieth Process therefore shews the common Vegetablo Manner of obtaining Oils from Seeds, Nuts, &c. by Expression or Squeezing.
Process twenty - first shews how to 21 make a kind of vegetable Milk, or Emulsion, by grinding the oily Seeds, Nuts, &c. in a Mor. XIX. 1782. : B
tar VOL. IV.'
for after hae's Repecitibe be.
tar with Water; which thus diffolves their oily Parts.
PROCESS twenty - second shews how Vegetables may be made to afford a large Proportion of Oil, barely by boiling them with Water, and scumming off the Oil as it rises to
the top. 23,24, 25, THE twenty-third shews how to procure 26,27, 28, chose called the Esential or Chemical Oils of 29.
Vegetables ; by Distillation with Water. And under this Article the Author ftrangely trespaffes against his own Rules, laid down in the beginning, to prevent the needless Repetition of any one Process a: for after having, in the prefent Processgiven an Example of the Manner of procuring these Oils, in the Leaves of Savin ; he repeats the fame Process no less than fix times over, viz. in Process 24, upon Mint; in Process 25, upon Lavender; in Process 26, upon Fennel
seed; in Process 27, upon Indian Cloves ; in - Process 28, upon Safiafras; and in Process 29, upon Cinnamon : so that we have here seven Processes to shew what might as well have been shewn under one ; especially after such Professions as the Author made at the beginning of doing nothing in vain, &c.
The thirtiteb Process Thews the Manner of distilling Oils per Defcenfum, by another Example in Cloves. And this too might have been omitted, as a thing sufficiently explained before, under Process eighteen; which shews the Manner of distilling per Defcensum. .
THỂre are several remarkable Particu. lars shewn by this. History of Oils. We will enumerate a few of them, viz. (1.) That the aromatic Virtue of Plants is contained in their
essential ? See Original, pag. 2, &c.